Process for dissolving a mixture of hafnium and zirconium phosphates and for separating hafnium and zirconium



. addedto the solution'being left, the obtained Patented eb. 22, 1927.

. UNITED STATES ANTON EDUARD VAN ARKEL AND JAN HENDRIX DE BOER,

LANDS, ASSIGNORS TQN. V. PHILIPS NETHERLANDS.

PROCESS No Drawing. Original application filed May 11, 1925,

DISSOLVING A IVIIXTURE OF HAFNI'UM ANDZIBCONIUM AND FOR SEPARATING HAFNIUM AND ZIRCONIUM.

OF EINDHOVEN, NETHER- GLOEILAMPENFABRIEKEN, OI" EINDHOVEN,

PHOSPHATES SerialNo. 29,561,3116. in the Netherlands June 6,

1924. Divided and this application filed January 4, 1926. Serial No. 79,258.

This invention relates to a'process of dissolvinghafnium and zirconium phosphates and of separating hafnium and zirconium 1n the solution thus obtained.

According to the invention the process may consist in dissolving a mixture of hafnium and zirconium phosphates in a medium containing concentrated sulphuric acid.

According to the invention hafnium and zirconium oxide can be precipitated out of the obtained solution of the hafnium and zirconium salts with the aid of a base or a basically reactingisubstance of sutiiciently high concentration of hydroxylions- According to the inventiona mixture of hafnium and zirconium compounds is separated by starting from the solution of said hafnium and zirconium salts in a medium containing concentrated sulphuric acid. This solution can be separated in many known ways. According 'to the invention very favourable results'are obtained by fractional precipitation of the solution preferably with the aid of water. The inventionmay be more clearly understood withrefen ence to some examples:

100 cubic centimetres of a suspension of a mixture of hafnium and zirconium phos-c phate, containing about 0,6 gramme of metal, dissolves entirely when 200 cubic centimet res of concentrated sulphuric acid are added. If the solution thus obtained is poured out into so large a quantity of has- -'ically reacting substance that the liquid shows an alkaline reaction until the end, a deposit of a mixture of hafnium and zirconium oxide is obtained.

It 100 cubic centimetres of a suspension of a mixture ofhafnium and zirconium phosphate containing 4% of hafnium metal relatively to the zirconium metal are dissolved in'fZOO cubic centimetres of concentrated sulphuric acid and if 30 cubic centimetres, of water are added to the thus obtained' solution'having a specific weight of 1,68, a deposit .Will'be isolated after some days. This deposit'has been found to contain 10% of hafnium relatively to zirconium. If again 30 cubic centimetres'of water are precipitate is found to contain 6% of hafstarting with a solution that can by bringing a mixture of hafnium and zir'- .nium relatively to zirconium. The specific weight-of the solution has now become 1,48. If this solution is diluted with an equal. quantity of water the precipitate formed is found to contain only 2% of hafnium relatively to zirconium. The deposit which is obtained by precipitating the remaining soiution *ith the aid of sodium-hydrate is found to be free of hafnium.

lVhat we claim is:

l. A process for converting a mixture of iafnium and zirconium phosphates, characterized in that said hafnium and zirconium salts are introduced into a medium containing concentrated sulphuric acid.

2. A process for converting a mixture of hafnium and zirconium phosphates, characterized in that said hafnium and zirconium salts are introduced into amedium containmg concentrated sulphuric acld and that from saidv solution hafnium and zirconium oxide are precipitated by means of a bas-,

starting with a solution that can be obtained 7y bringing a mixture of hafnium and zirconium phosphates in a medium-that contains concentrated sulphuric acid and submitting said solution tofractional tion. i c I V 5. A process of separating hafnium and zirconium compounds, characterized by conium phosphates in a medium that contains concentrated sulphuric acid and sublllllltlllgsitld solution to fractlonal precipie tationi In testimonywhereof we afiix our sigmabe obtained tures at the cityof Eindhoven'this 7th day of December A. D; 1925. ANTON EDUARD VAN ARKEL.

. JAN HENDRIK DE BOER' 

